Instruction Manual – Ramsond CUT series plasma cutters Rev 10-0993
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Page 5
SECTION 2. - BASIC PRINCIPALS AND TERMINOLOGY OF PLASMA CUTTING
A. Plasma Defined
Plasma cutters work by sending a pressurized
gas, such as air, through a small channel. In the
center of this channel, you’ll find a negatively
charged electrode. The electrode is at the center,
and the nozzle is just below it. The swirl ring
causes the plasma to turn rapidly as it passes.
When you apply power to the negative electrode
and you touch the tip of the nozzle to the metal,
the connection creates a circuit. A powerful spark
is generated between the electrode and the
metal. As the inert gas passes through the
channel, the spark heats the gas until it reaches
the fourth state of matter. This reaction creates a
stream of directed plasma, approximately 30,000
F or more and moving at 20,000 feet per second
that reduces metal to vapor and molten slag.
The plasma itself conducts electrical current. The
cycle of creating the arc is continuous as long as
power is supplied to the electrode and the plasma
stays in contact with the metal that is being cut.
The cutter nozzle has a second set of channels.
These channels release a constant flow of
shielding gas around the cutting area. The
pressure of this gas flow effectively controls the
radius of the plasma beam.
NOTE! This machine is designed to use only
compressed air as the “gas.”
B. Voltage Regulation
The Automatic Voltage Compensation
Circuit prevents voltage load from exceeding
maximum in accordance with the main technical
data sheet and shortening the life of the machine.
C. Thermal Protection
The thermal protection circuits will engage if unit
exceeds duty cycle. This will cause the machine
to stop working. The indicator will be lit on the
front of the machine. The fan will continue to run
until the unit cools down. When it reaches an
acceptable temperature, the unit will operate
again.
D. Duty Cycle
Duty cycle is the percentage of on time in a 10
minute period in which the machine can be
operated continually, in an environment of a
specified temperature.
Exceeding duty cycle ratings will cause the
thermal overload protection circuit to become
energized and shut down output until the unit
cools to normal operating temperature. Continual
exceeding of duty cycle ratings can cause
damage to the machine.
